In a medium saucepan over medium heat, combine sugar, water, and mint leaves. Stir until mixture comes to a boil; reduce heat to low and simmer 5 minutes. Remove from heat, cover, and let stand approximately 10 minutes.
Place a fine strainer over a large bowl and pour the mint syrup mixture through (straining out the mint leaves).
Add grapefruit juice to the strained syrup mixture; stir until thoroughly blended.
Ice Cream Maker - Transfer mixture to ice cream maker, process according to manufacturer's instructions.
Freezer Method - Pour into container, cover, and place mixture in the freezer. When it is semi-solid, mash it up with a fork and refreeze again. When frozen, place in a food processor or blender and process until smooth. Cover and refreeze until serving time.
NOTE: Can be prepared 3 days in advance. Cover and keep frozen.
When ready to serve, use a small melon baller. I like to use 3 scoops per person in a decorative stem glass. A dd mint sprig for garnish and serve.
Minty Grapefruit Sorbet Recipe: https://whatscookingamerica.net/SorbetGrapefruit.htm